The development of cells and multi-cellular structures is influenced by the extracellular matrix (ECM). Hyaluronic acid (HA) is a major glycosaminoglycan component of the ECM.
HA is one of the most abundant glycosaminoglycans (GAGs) in the female reproductive tract (Lee and Ax (1984); Toole (1991)). Supplementation of both semi-defined and defined culture media with HA has been shown to improve the development of in vitro matured and fertilised bovine embryos to the blastocyst stage without affecting embryo quality and post-freeze survival.
The inclusion of HA in culture media has been proposed in order to increase the efficiency of in vitro blastocyst production from in vitro matured bovine oocytes (Furnus et al. (1998)). Indeed, in separate studies, the highest rates of implantation and foetal development after blastocyst transfer were observed when HA was the macromolecule in the culture media (Gardner et al. (1999)).
Several commercial embryo transfer media products supplemented with HA are available (EmbryoGlue® Vitrolife, UTM™ Medicult). Despite the availability of these products, the basis for the beneficial effects of HA on implantation and foetal development are not well understood.
HA may play a biophysical role mediating interactions between the embryo and the surface of the endometrium. Furnus et al., (1998) have suggested that HA might benefit embryo development per se, or regulate the action of factors synthesised by the embryo, acting in an autocrine manner.
Gardner et al. (1999) suggested that the highest cell numbers and hatching rates obtained in their study occurred when both serum albumin and HA were present in the same medium. It was proposed by these authors that embryo culture media should contain both serum albumin and HA, while transfer media need only contain HA.
It is an object of the invention to provide carbohydrate-lipid constructs for use in localising carbohydrate to the surface of embryos.
It is a further object of the invention to provide carbohydrate-lipid constructs for use in influencing the development of cells and multi-cellular structures.
It is a yet further object of the invention to provide a method for improving the likelihood of successful outcomes from assisted reproductive techniques.
These objects are to be read disjunctively with the object to at least provide the public with a useful choice.